Parasitosis has been reducing as the results of improvement in environmental hygiene and progress of anthelmintics, but recently imported parasitosis, zoonotic parasitosis, opportunistic parasitosis and parasitosis derived from raw foods are increasing, as a result various parasitoses become an issue. In livestock farming and agriculture, parasitosis causes great economic burden at present. Among parasitoses, with regard to helminth infection, many compounds such as ivermectin, mebendazole, praziquantel, etc. are used.
However, anthelmintics such as ivermectin, mebendazole and praziquantel are not always satisfactory in view of effectiveness and toxicities, as a result new agents are still demanded.
We have focused to study NADH-fumarate reductase in the electron transport system, one of hopeful targets for anthelmintics, and continued to explore inhibitors against such enzyme from microbial culture products, as a result, we have found FT-0554 substance (nafuredin). The international patent application of this substance was published as the international publication WO99/24439, which was transferred to the U.S. and the application Ser. No. 09/509770 was given.
The microorganism having ability to produce FT-0554 substance (nafuredin) is Aspergillus niger FT-0554 belonging to fungi, the strain of which was deposited the International Patent Organism Depository, National Institute of Advanced Industrial Science and Technology, and given a permanent depository No. as FERM BP-6443. Taxonomical properties of the strain are briefly described as follows.
Culturing properties on various agar media such as Czapek-yeast extract agar, malt extract agar, 20% sucrose Czapek-yeast extract agar, potato dextrose agar and Miura's medium, are good growth with velvety and smooth penumbra. Diameter of colony is 40 mm–85 mm. Color tone of the surface of colony is burned umber. Color tone of the reverse of colony is pale yellow or white.
Morphological properties on Czapek-yeast extract agar, malt extract agar, 20% sucrose Czapek-yeast extract agar and potato dextrose agar, containing 50% of seawater (salt content, 3.4%) are good growth with good bearing conidia.
Physiological properties are: optimum growth condition: pH 5–7 at 16–36° C. and in concentration of seawater 50–100%. Growth ranges are pH 3–10, at 12–45° C. and in concentration of seawater 0–100%.